Background: Knowledge concerning the various anomalies of aortic arch derivatives is important to the clinician, radiologist and surgeon. This knowledge aids in evaluating the finding in cases in which symptoms may result from the vascular anomalies. Aim: to study the branching pattern of aortic arch and its clinical importance Materials and Methods: A total of 50 dead foetuses (Male-30; Females-20) collected from the Department of Obstetrics and Gynaecology and 10 adult cadavers (Male-7; Female-3) from the Department of Anatomy, Kurnool was utilized for the present study. The mediastinum was opened, and the branching pattern of the arch of aorta was observed Results: The present study is carried out on 60 specimens of 50 dead fetuses (Male-33; Female-17) and 10 cadavers (Male-7; Female-3). The normal branching pattern (Type-I) of Arch of Aorta was observed in 47 (78.3%) and the most common variation of a common stem for the brachiocephalic trunk and left common carotid artery (Type-II) observed in 8 (13.3%) specimens. The left vertebral artery arose directly from the Arch of the Aorta (Type-III) with an incidence of 4 (6.6%) and one specimen (1.7%) has a common stem (Type-IX) for the left common carotid and left subclavian artery was noted in the present study. Conclusion: The present study could be of valuable information to radiologists and surgeons. Further studies on the Aortic Arch and its branches in live individuals will enable us to design stents
The aortic arch is defined as the segment of the aorta between a line at a right angle proximal to the brachiocephalic artery origin and extending to a line drawn at a right angle distal to the left subclavian artery [1].The aortic arch begins behind the right margin of the sternum at the level of the second costal cartilage and ends on the left side of the lower border of the fourth thoracic vertebra. It is a continuation of the ascending aorta and gives three branches brachiocephalic trunk, left common carotid artery and left subclavian artery [2,3].The various anomalies of the Aortic Arch and its branches are often associated with other congenital anomalies such as tetralogy of Fallot, tricuspid atresia, truncus arteriosus, transposition of great vessels, ventricular septal defect [4], pulmonary stenosis, double outlet right ventricle, patent ductus arteriosus [5], persistent trigeminal artery, trachea-oesophageal fistula, an anomalous right recurrent branch of the vagus and right thoracic duct [6].The current study aimed to report the branching patterns of the aortic arch and its clinical importance
50 dead foetuses (Male-30; Females-20) collected from the Department of Obstetrics and Gynaecology and 10 adult cadavers (Male-7; Female-3) from the Department of Anatomy, Kurnool were utilized for the present study. The mediastinum was opened, brachiocephalic veins and the upper part of the superior vena cava were identified, inferior thyroid, internal thoracic, and left superior intercostal veins were found and followed them into the brachiocephalic veins. Displacing the veins, the aortic arch was exposed along with the branches arise from its convex surface was recorded and photographed in the present study
The present study is carried out on 60 specimens of 50 dead fetuses (Male-33; Female-17) and 10 cadavers (Male-7; Female-3). The normal branching pattern (Type-I) of the arch of the aorta in47(78.3%) specimens was observed. The most common variation is the presence of a common stem for the brachiocephalic trunk and left common carotid artery (Type-II) observed in 8 (13.3%) of specimens (Figure 1).We also noted, that one specimen has a common stem(Type-IX) for the left common carotid and left subclavian artery (Figure 2). The left vertebral artery arose directly from the arch of the aorta (Type-III) between the left common carotid artery and left subclavian artery was observed in 4 (6.6%) of the specimens (Figure 3 & Figure 4-Adult). The arch of the aorta showed a normal branching pattern with 3 branches in 78.3% of cases and showed a variant branching pattern with 2 branches in 15% of cases and 4 branches in 6.6% of cases (Table 1). The brachiocephalic trunk arises normally from the arch of the aorta in all cases. The Left common carotid artery normally arose from the arch of the aorta in 85% of cases and showed variant origin from the right brachiocephalic trunk in 13.3% of cases and from the left brachiocephalic trunk in 1.7% of cases (Table 2). The left subclavian artery normally arose from the arch of the aorta in 98.3% of cases and showed variant origin from the left brachiocephalic trunk
in 1.7% of cases (Table 3). An additional branch (left vertebral artery) was noted from the Arch of Aorta in 6.6% of cases in the present study (Table 4).
Variations in the branching pattern of the aortic arch range from differences in the distance between the origins of different branches to several branches [7, 8]. In the present study, 60 aortic Arches (Fetal-50; Adult-10) were dissected and studied concerning the branches arising from them and specimens were divided into various types of classification [9].The normal branching pattern of the aortic arch (Type-I) was observed in 78.3% of the specimens. The most common anomaly was the presence of a common stem for the brachiocephalic and left common carotid arteries (Type-II) was observed in 13.3% of the specimens. Sunitha Vinnakota et al reported the Type-II branching pattern with a mere incidence of 14.2% [10]. The aortic arch type- II branching pattern with higher incidence of 37% in American Negros, and 17.8% in American whites was observed[11].This anomalous branching pattern may lead to increase blood flow in the left common carotid artery. The anomalies of the aortic arch branching pattern could lead to cerebral abnormalities by altering the pattern of flow in cerebral vessels [12]. The next most common anomaly was observed in 6.6% of specimens, in which the left vertebral artery arose directly from the aortic arch in between the origins of the left common carotid and the left subclavian arteries (Type-III), and one specimen (1.7%) had a common stem for the left common carotid and left subclavian arteries (Type-IX) in the present study. The aortic arch with type-III branching pattern with an incidence of 7-8% of cases and type–IX branching pattern with an incidence of 2% was observed in previous literature [13,14].The direct origin of the left vertebral artery from the arch of the aorta increases blood flow in the left vertebral artery. The direct flow of blood from the aorta to the brain or the imbalance of the flow of blood on the left and right sides at the circle of Willis may be the cause of increased incidence of cerebrovascular diseases in cadavers having type-II and type-III patterns of aortic arch [15]. The current study results are in agreement with the majority of the previous literature and acknowledge the significant role in understanding the branching pattern of the arch of the aorta in fetuses and adult humans with its clinical importance.
The present study could be of valuable information to radiologists and surgeons. Further studies on the Aortic Arch and its branches in live individuals will enable us to design stents.
Acknowledgements
The authors are also grateful to authors, editors and publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed.
Conflict of Interest: NIL